AbstractThe High-redshift Emission Line Survey (HiZELS) is exploiting narrow-band filters in the J, H and K bands on WFCAM/UKIRT to undertake deep & wide extragalactic surveys for emission-line galaxies. HiZELS is primarily targeting the redshifted H-alpha emission line at z=0.84 (J), z=1.47(H) and z=2.23(K) over volumes of >106 Mpc3, and, with the addition of a perfectly matched [OII] Subaru narrow-band survey, is resulting in samples of ~1000 high-z emitters at each epoch. By taking advantage of such large and well-defined samples, obtained over the best well-studied fields, we have measured the detailed evolution of the H-alpha (and [OII]) luminosity function and the star formation history of the Universe up to z>2, for the first time. Furthermore, even more importantly, by exploring such large samples and conducting detailed morphological, dust, clustering, environmental and mass studies (and quantifying/identifying key inter-dependences) we have made significant progress in understanding the main drivers of galaxy formation and evolution.